While I agree that achievements are a social flaw, and that some are pretty ridiculous (soon you'll get an achievement for clicking somewhere on the user interface), or just a benchmark on how far you played through the tutorial, or explored various game settings/ends, they would be a way to promote players within the playing community, when they invest themselves in some narrow aspects of the game, for example "Kill Boss X in the first Y days" or "Kill all bosses using a pointy weapon only" whereas the game doesn't force other players to act like this. Other achievements for dedication/"no-life" playstyle could be "Collect X gold coins" or "Fill first chest full of bones".

Other achievements could be mischevious and fun, like mini games: "Fall into water from more than 35 meters" (where exact number would correspond to the highest "tower" built on top of a fairly rare high coastal rock)

Alas, I don't know if there could be an achievement for "Build a nice-looking castle with twenty rooms", which in contrast would truely be a community achievement.